Colour couplers are known to belong to a number of classes, for example magenta dye-forming couplers can be pyrazolones, pyrazolotriazoles and pyrazolobenzimidazoles while yellow dye-forming couplers can be acetanilides.
Problem to be Solved by the Invention
There is always a need for new classes of couplers that have advantages over those already known to the art.